用嵌套列表连接两个列表

Question

Trying to find a way to join two lists along with nested lists through LINQ or PLINQ.

I have List A , List B and wanted to join these two with their parent and child properties.

I have tried the following

List<data> result = A.Where(o=>foo.Any(x=>x.headerid=o.headerid)) &&
o.details.Any(y=>foo.Any(z=>z.headerid=o.headerid && z.detailid=y.detailid)).ToList();

But not sure this is the right way of doing it. Here the foo list is being scanned twice. I wanted to have a join query to fix this be it lambda or join query. Preferably join query.

class filterclass
{
   public string headerid;
   public string detailid;
}

class data 
{
  public string headerid;
  public string headername;
  public List<Detail> details;
  //...
}

class detail
{
  public string detailid;
  public string detailname;
  //...
}

List<data> A = new List<data>();
List<filterclass> foo = new List<filterclass>();

Now my need is to join A and foo with the fields like A.headerid = foo.headerid and A.detail.detailid = foo.detailid .

Thing is A.detail is the nested list and I am not sure how to join it. Not sure whether the FirstOrDefault or All will work in this case. Also don't want to loop

Any help is appreciated and thanks in advance.

I need to have a LINQ JOIN query.

Answer 1

You can use the Concat Extension Method for joining lists:

var combinedList = list1.Concat(list2);

And for your specific example:

var combinedList = A.Concat(foo);

It creates an instance of IEnumerable<T> which will enumerate the elements of list1 and list2 in that order.